From patchwork Wed Jul 1 09:29:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: robbieko X-Patchwork-Id: 11635923 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C8B6692A for ; Wed, 1 Jul 2020 09:35:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AFB84206C3 for ; Wed, 1 Jul 2020 09:35:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=synology.com header.i=@synology.com header.b="PYKi+X+S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729266AbgGAJfc (ORCPT ); Wed, 1 Jul 2020 05:35:32 -0400 Received: from mail.synology.com ([211.23.38.101]:56984 "EHLO synology.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726715AbgGAJfc (ORCPT ); Wed, 1 Jul 2020 05:35:32 -0400 Received: from localhost.localdomain (unknown [10.17.32.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by synology.com (Postfix) with ESMTPSA id 7AF91CE782A2; Wed, 1 Jul 2020 17:30:01 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synology.com; s=123; t=1593595801; bh=vmaLzrgyXsA/w7RySgTkfZcXycOo9zcOG7ic0XlP7Rk=; h=From:To:Cc:Subject:Date; b=PYKi+X+SpK/bPvojdhCa4TCTS86+Idi3UlcVbvu+l7/6EfkYkwSfl9K7HlL74Ialg EOTA1gGxVCjLDV42XBMm10HV9l3lyjLu0s6jA2LyjdPRFgD7yX+85KMDtsIVcwMz3n WGJzkCEvgvgqCD418f94mGGbhRO4kQNfJInett6o= From: robbieko To: linux-btrfs@vger.kernel.org Cc: Robbie Ko Subject: [PATCH] btrfs: speedup mount time with force readahead chunk tree Date: Wed, 1 Jul 2020 17:29:57 +0800 Message-Id: <20200701092957.20870-1-robbieko@synology.com> X-Mailer: git-send-email 2.17.1 X-Synology-MCP-Status: no X-Synology-Spam-Flag: no X-Synology-Spam-Status: score=0, required 6, WHITELIST_FROM_ADDRESS 0 X-Synology-Virus-Status: no Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Robbie Ko When mounting, we always need to read the whole chunk tree, when there are too many chunk items, most of the time is spent on btrfs_read_chunk_tree, because we only read one leaf at a time. We fix this by adding a new readahead mode READA_FORWARD_FORCE, which reads all the leaves after the key in the node when reading a level 1 node. Signed-off-by: Robbie Ko --- fs/btrfs/ctree.c | 7 +++++-- fs/btrfs/ctree.h | 2 +- fs/btrfs/volumes.c | 1 + 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 3a7648bff42c..abb9108e2d7d 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2194,7 +2194,7 @@ static void reada_for_search(struct btrfs_fs_info *fs_info, if (nr == 0) break; nr--; - } else if (path->reada == READA_FORWARD) { + } else if (path->reada == READA_FORWARD || path->reada == READA_FORWARD_FORCE) { nr++; if (nr >= nritems) break; @@ -2205,12 +2205,15 @@ static void reada_for_search(struct btrfs_fs_info *fs_info, break; } search = btrfs_node_blockptr(node, nr); - if ((search <= target && target - search <= 65536) || + if ((path->reada == READA_FORWARD_FORCE) || + (search <= target && target - search <= 65536) || (search > target && search - target <= 65536)) { readahead_tree_block(fs_info, search); nread += blocksize; } nscan++; + if (path->reada == READA_FORWARD_FORCE) + continue; if ((nread > 65536 || nscan > 32)) break; } diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index d404cce8ae40..808bcbdc9530 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -353,7 +353,7 @@ struct btrfs_node { * The slots array records the index of the item or block pointer * used while walking the tree. */ -enum { READA_NONE, READA_BACK, READA_FORWARD }; +enum { READA_NONE, READA_BACK, READA_FORWARD, READA_FORWARD_FORCE }; struct btrfs_path { struct extent_buffer *nodes[BTRFS_MAX_LEVEL]; int slots[BTRFS_MAX_LEVEL]; diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 0d6e785bcb98..78fd65abff69 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -7043,6 +7043,7 @@ int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info) path = btrfs_alloc_path(); if (!path) return -ENOMEM; + path->reada = READA_FORWARD_FORCE; /* * uuid_mutex is needed only if we are mounting a sprout FS